A shikakenin was an under-the-cover trade that undertook killing in Edo. Hanemon of Otowa, an agency that introduced laborers and maids, was also one of these. Katsugoro Iseya was a timber dealer who had come in as a client. His target was the constructions magistrate Hanno, and the Tatsumiya who sipped on the benefits. Hanemon who had a stong code towards killing, where he would only kill those who do no good to be in the world, accepts this request. Baian Fujieda, a needle doctor would carry out the killing. However, the professional killer Baian fails to bring down Tatsumiya. Hanemon then looks to another shikakenin, the ronin Sanai Nishimura for the role. Although Sanai's ability with the sword is good, he lives poorly in a tenement, and accepts this commission on the condition that it is kept a secret from his wife and child. Here, they close in on Hanno and Tatsumiya again...

主角表面上有正当的职业，但实际上却是替天行道的杀手。

Ronin Nišimura a akupunkturista doktor Baian jsou ve skutečnosti nájemní zabijáci působící v podsvětí Eda, řídící se svým vlastním přísným kodexem. Jejich poslední „zakázky“ je však postaví před vážná dilemata: zatímco Nišimura zvažuje přijmout nabídku magistrátního představitele a začít se živit „poctivě“ jako úředník (tedy hlavně z úplatků), Baian si není jist, zda žena, kterou má zabít, není jeho dlouho ztracená sestra.